Manufacture of containers



H. F. WATERS Imncma 0F connmsns Oct. 15, 1946.

Original Filed Jul 18, 1936 INVENTOR jfarzywafei's ATTORNEY I Patented Oct. 15, 1946 MANUFACTURE OF CONTAINERS Harry F. Waters, New York, N. Y. Original application July 18, 1936, Serial No.

Divided and this application November 12, 1941, Serial No. 418,745

' 2 Claims. (01. 93-551) This invention relates to improvements in cartons and containers and more particularly to improved apparatus for and method of forming a carton for the packaging of liquids.

One of the objects of the invention is to provide an improved apparatus for and method of forming a container designed primarily for the packaging of liquids in which a continuous, unbroken surface of a liquidproof character is presented to the contents of the container, the said surface likewise extending through the seams necessarily formed during the construction of the said container.

Another object of this invention is to provide an improved method of, and apparatus for, securing the bottom of a carton of the character described and the cover therefor in place after the carton has been filled, in which use is made of a combination of heat sealing members and resilient backing members. By such mechanism irregularities in the thickness of the plies to be sealed are compensated for so that a continuous, unbroken seal is provided.

Other objects of this invention will become more apparent as the description of the various embodiments thereof proceeds.

Referring now more particularly to the draw- 1 ing:

Fig. 1 is a plan view of the blank from which the carton may be made;

Fig. 2 is a view in perspective of the completed carton with the cover in position;

Fig. 3 is a horizontal, sectional view taken along the lines 3-3 of Fig. 2;

Fig. 4 is a vertical, sectional view taken along lines 4-4 of Fig. 3;

Fig. 5 i an enlarged vertical, sectional view of a portion of a bottom of the container including The present application is a division of my copendingapplication Ser. No. 91,365, filed July 18, 1936.

Referring now to the drawing and more particularly to Fig. 1, there is shown a blank from which the carton is formed. The blank comprises a, substantially rectangular strip of material to which are attached the top and bottom one of thesidewalls thereof showing the manner in which the seal between the cover and the side wall is made;

Fig. 6 is an enlarged sectional view showing the construction of the seam in the body of the container;

Fig. 7 is a sectional view showing a modified bottom construction;

Fig. 8 is a view in perspective of a modified form of carton with the top and bottom closures being omitted; I

Fig. 9 is a view similar to Fig. 7, but showing a still further modified form of carton with top and bottom closures; and

Fig. 10 is an enlarged detail view of the bottom of the carton showing the mechanism employed for securing the said bottom in place.

closures. This strip is divided into end and sidewalls l0, H), H, II, respectively, by parallel score lines l2 extending across the shorter dimensions of the strip. Attached to the outer edge of endwall [0 and sidewall ll along score lines I3 and M, respectively, are the securing fiaps l5 and I6 which, in the embodiment shown, are coextensive in length with said end and sidewalls. A closure, in the particular construction shown, the bottom closure, is secured to one edge of the sidewall I I along a score line I! and comprises a bottom or central panel I 8 having attached thereto along its marginal edges, defined by score lines I9, 20, 2| and 22, flaps 23, 24, 25 and 26. The flaps 23 and 24 extend beyond the confines of the central panel and have their end edges coextensive with score lines I! and 21. In order to permit the excess of material in the flaps to be folded into closing position when the carton is assembled, score lines 28 are provided which extend diagonally from the outer corners of the flaps 23 and 24 to the juncture of score lines l9,

2| and 22, and score lines 20, 2| and 22. A sealing flap 29 is secured to flap 26 along score line 21. The bottom closure is secured to the main body of the blank along the score line H, cuts 30 are provided to separate flaps 23 and 24 from the main body portion of the blank.

The cover for the carton is carried by sidewall II' and is positioned on that side of the blank opposite to that to which the bottom is secured. The construction of the cover is usually identical to the bottom construction and comprises a bottom or central panel 3| havin fiaps 32, 33, 34 and 35 attached to the marginal edges thereof. A cover is attached to the sidewall H along score line 23 and a sealing flap 31 is secured to flap 35 along score line 38. Diagonally positioned score lines 39 are provided to permit the excess of material in flaps 32 and 33 to be folded into operative position. The flaps 32 and 33 are separated from the main body portion of the blank by cuts 40.

The blank'is preferably provided on one side with a coating, designated generally by the letter A, of a liquidproof, thermoplastic character which may be applied either before or after the blank is formed. For some purposes I prefer to use a laminated stock comprising a sheet of Pliofilm or similar material secured with any suitable type of adhesive to paper. As a possible means of economy in manufacture, the bottom and cover may be formed separately from the body portion of the blank.

In forming the carton, the body portion is folded along score lines l2, bringing the sealing flaps l and I6 into operative relation. Since one of the difficulties encountered in the formation of liquidproof containers resides in the fact that leakage usually occurs through the seams formed during the construction of the container, I have provided an improved form of scam in which the coated surfaces are brought into contacting relation. Thus in Fig. 3 it will be noted that the sealing flap i5 is folded against the outer side of endwall Ill so as to present a coated surface to the sealing flap l6. Since the material used to provide a suitable liquidproof surface is preferably of a thermoplastic character, the seam may readily be formed by the application of heat and pressure or by the application of heat alone. The heat causes the liquidproof material to flow so that the line of demarcation of the seam, which would normally be present in the interior of the container, is substantially obliterated as is indicated in Fig. 6 at 42. In commercial operation the flow of the thermoplastic material not only obliterates any evidence of the seam, but the thermoplastic material carried by the flaps is suflicient to form, with the material on the end and sidewalls, a surface which is unbroken and continuous. By this construction therefore, leakage of the contents of the carton through the seams by capillarity or wicking cannot take place.

The next step in the formation of the carton is to secure the bottom in place. Although this can be accomplished in many ways, flaps 23, 24, 25 and 26 are preferably folded normal to the central portion. The excess of material in flaps 23 and 24 is then folded inwardly along score lines 28 to provide, at the juncture of the corners of the bottom of the container, fins or tucks 43. Due to the fact that these fins are formed by folding the material inwardly along the score lines 28, all of the joining surfaces of the bottom present a liquidproof, thermoplastic material to the walls of the carton so that when the bottom is finally secured into position by the application of heat and pressure or by the application of heat alone, the same type of liquidproof surface will be presented to the contents of the carton as is presented by the side seam of the said carton. Sealing flap 29 is brought around the end edge of sidewall II and secured thereto by means of the liquidproof material carried by the bottom. However, it will be noted that the line of demarcation between the bottom and walls to which the bottom is secured is substantially obliterated by the liquidproof material, as is indicated at 44, Fig. 5. After the container has been filled with the desired liquid the cover 3| is secured in place. Since the top closure is identical to the bottom construction no further description is deemed to be necessary. It will be noted that the tucks or fins 43' are identical to the tucks or fins 43.

As has been previously pointed out, it might be desirable to form the top and bottom covers separate from the main body portion of the blank. If this is done it will become apparent that various types of bottom and top closures may be used. Thus in Fig. 8 there is shown in perspective the main body portion of a carton formed from a substantially rectangular blank. The side seam 45 is identical in construction with the side seam previously described and further description thereof is deemed to be unnecessary. The bottom construction may be of several diflerent types. Thus in Fig. 7 I have shown a bottom 46 having a coating 41 preferably of a liquidproof, thermoplastic character. This bottom is preferably of the pressed variety, that is, by means of pressure the marginal rim 4B is formed, by means of which the said bottom is secured to the walls of the carton. It will be noted that the same principle is utilized in the formation of the bottom, namely, the adhesion of coated surfaces so as to provide an inner surface for the carton which is continuous and unbroken throughout. Again all evidence of the seam is substantially obliterated due to the presence of the liquidproof surface indicated at 49. Alternatively, the bottom may be of the construction shown in Fig. 9 wherein the bottom 50 is provided with a continuous marginal rim 5| having a reversely bent portion 52 extending over the end edges of the carton walls. The coating material 53 is in contact with the coating material of the carton walls so that when the bottom is secured in position by means of heat and pressure, or by heat alone, the flow of the coating material will not only secure the bottom in place, but will provide a continuous, unbroken, liquidproof coating at the line of juncture of the bottom with the walls of the container.

In Fig. 10 there is illustrated one method and a preferred form of mechanism which may be used to secure the end closures of the carton to the walls thereof. The mechanism comprises a plurality of reciprocable heat sealing bars 54 having any conventional form of heating unit 55 secured to a suitable source of current, not shown. In order to provide a backing member against which the sealing bars will work, there is provided amandrel 56 having an operating or working member 51 made of expansible, resilient material, as, for example, rubber. The member 51 is confined between a plate 56A fixed to the mandrel 56 and a plate 563 movable relative to the mandrel and adapted to be adjusted toward and from the plate 56A by movement of a nut 58 threaded upon the mandrel. By adjusting the nut 58 to press the plate 563 against the working member 51 to compress it between the plates 56B and 56A and cause it to expand in a direction normal to the direction of compression. The member 51 may thus be forced against the interior walls of the bottom. When the heat sealing bars are moved into operative position, the continuation of heat and pressure will cause a flow of the thermoplastic, liquidproof material, thereby sealing the bottom flaps to the respective walls of the carton. The resiliency of the working member will insure a perfect joining of the coating material carried by the bottom of the carton in spite of any irregularities or differences in thickness of said bottom and carton wall, due to the fact that the resiliency of the working member will compensate for these variations and permit a substantially constant pressure throughout the area to be sealed.

I claim:

1. A'process for securing a closure to a container provided on its interior surface with a thermoplastic liquidproof material which comprises coating the closure with a thermoplastic liquidproof material, bringing into juxtaposition only coated surfaces 01' the closure and container,

5 applying heat and pressure to bond said surfaces together by pr ssing said surfaces and the plies of the container and closure between a heated pressure member and a resilient backing member whereby to distribute said pressure substantially 5 uniformly to all parts of the area to be bonded.

2. In a process for sealing a closure to a container wherein said closure and said container are each provided on the mutually contacting surfaces thereof with a liquidproof thermoplastic mate- 

